Portable power-driven saw guard



Oct. 11, 1960' H. w. BORK PORTABLE POWER-DRIVEN SAW GUARD Filed March31. 1958 v 2 Sheets-Sheet 1 56 INVENTOR.

H. w.- BORK PORTABLE POWER-DRIVEN SAW GUARD 2 m 1, 5. /m m w z 1 l r v n8 1| It I INVENTOR.

United Sttes Patent O PORTABLE POWER-DRIVEN SAW GUARD Hugo W. Bork,Chicago, Ill., assignor to Ski] Corporation, Chicago, 11]., acorporation of Delaware Filed Mar. 31, 195s, Ser. No. 125,190

4 Claims. or. 143-159 In spite of safety precautions taken by most 1 Onepurpose of the present invention is to provide, in

saws of this type, a new and improved safety means both in the saw bladeguard and in the blade-changing mechs -Another object is to providesafety means for the purpose intended that is simple in construction,relatively in expensive, and requiring little or no care by theoperator.

While the foregoing statements are indicative in a general way of thenature of the invention, other objects and advantages will be apparentto those skilled in the art upon a full understanding of theconstruction, arrangement, and operation of the parts comprising the newsafety means. A preferred embodiment of invention is presented forexemplification, but it will of course be appreciated that the inventionis susceptible of incorporation in other structurally modified formscoming equally withr in the scope of the appended claims.

In the accompanying drawings:

) 1 Fig. 1 is a side view of a saw whichincorporates the safety means ofthe invention;

Fig. 2 is a partially sectioned top view of the saw of Fig. 1;

Fig. 3 "is a front view of the saw;

Fig. 4 is a view similar to Fig. 3 with-the foot assembly removed andpartly in vertical section;

Fig. 5 is a view on line 55 of Fig. 3; and Fig.6 is an enlarged 'view ofthe arbor lock safety means shown in the partially sectioned view ofFig. 2;

For purposes of illustration, a saw having a vertical adjustmentmechanism for depth of cut of saw blade such as shown and described inArthur N. Emmons Patent No. 1,848,330 issued March 8, 1932 is used. Butthe invention is not limited to this type of adjustment as certainfeatures of the invention are applicable to any saw of this type 'knownto applicant while other features are applicable to any saw of thegeneral type where the foot support is vertically adjustable relative tothe forward portion of the. upper saw guard and the motor housing.

In the drawings, Figs. 2, 3 and 4, is shown a motor housing 10 withinwhich is mounted a motor (not shown) having an armature shaft 12 formedwith a pinion on its outer end. A suitable driven saw arbor 13 ismounted in said housing in a bearing 14 and operatively connected tosaid armature shaft pinion 12 through a gear 16. The arbor shaft 13 maybe splined to receive the splined gear 16 and a splined annular arborlocking plate 18 to be described later.

Patented Oct; 11, 1960 An inner saw blade washer 20 is mounted over thearbor and bears against the inner surface of a saw blade 21 that ismounted or clamped between washer 20 and outer washer 22 that is splinedto interlock and rotate with the arbor. A threaded member such as a sawstud or bolt 23 holds this assembly together When threaded into the endof the arbor that is apertured to receive it.

A bearing retainer 24 is'mounted to the saw housing in spaced relationto the'inner washer 20 and rotatably mounted in any suitable manner overretainer 24 is an upper saw guard member 26 that islimited in itsrotating movement by a cam means such as the slot 28 (Figs. 1, 3) sothat the forward lip portion 30 of upper guard member 26 may bemaintained in a guarded position ad jacent the foot member assembly 32by a cooperating cam pin 34 of the foot member.

The foot member assembly includes a substantially flat plate member 35underlying the housing 10 and forming a support for the housing andentire saw. In normal operation it slides over a work piece taking mostif not all of the weight of the saw from the operator. Mountedintegrally on the footmember, and for the purposes of this embodimentconsidered as part of it, is a quadrant angle guide 36 by which the sawhousing and the blade maybe mounted angularly to the foot member 32 ,forangular cuts in a work piece. Attached to guide 36 is a vertical guidemember 38 having a threaded pin, not "shown, extending through the slotof angle guide 36 and elainpable thereto in various adjustedrelationships by the clamping bolt 40.

- In vertical guide 38 and housing 10 are complementary vertical" guideways 41, 42 (Fig. 5) whereby housing 10 and its saw blade may belifted.or.slid with respect to foot member 32 and its vertical guide 38 sothat the depth of cut of the saw blade 21 below footmember 32 may beregulated. A clamping guideplate 43 having a threaded bolt 44 extendingthrough vertical guide'38 and tightened by clamp handle 45 may be usedtohold the 7 housing in its predetermined adjusted position. Referenceismade to the Arthur N. Emmons patent mentioned above for a more specificdescription of this type of angular and vertical adjusting mechanism. Ascam actuating pin34 is mounted to vertical guide 38 it 'is always heldto quadrant arm 36 as part of the foot member assembly and remainsstationary upon vertical depth adjustment. Consequently as the housing10, the arbor, blade and guard assembly are lifted, cam arm 34'rides incam slot 28 of the upper guard member 26 forcing the guard to rotatewith respect to the housing to hold the forward portion 30 of the guardadjacent foot member 32 in a continuous guarded relationship for the sawblade.

In previous devices, upon vertical adjustment of the type shown, theupper guard and its forward lip portion rose' with the housing, oftenleaving a space of one or two or more inches unguarded between the footmember and guard member, exposing the blade to this extent andincreasing the danger to the operator. With applicant's simple rotatableupper guard and cam means cooperating with the guard and foot members,this danger is eliminated. I

With reference to the mounting of saw blade 21 on saw arbor 13, someyears ago the blade normally was fitted to the inner or outer washermember which in turn was keyed to the arbor shaft or the saw was mounteddirectly to the shaft. Some saws are still made this way today. Inchanging saw blades, the saw blade was clamped tight by placing a nailor screw driver through the blade teeth and Wedging it against the footassembly.

If this rough clampingmethod slipped or failed, the operator receivedsome badly skinned knuckles from the blade teeth or guards.

f When a blade is directly or indirectly keyed to the arbor there isalways danger of kick-back and injury to the user if a knot is struck orthe saw is overloaded in green wood. For these reasons, clutch devicesof various kinds have become common so .that the blade ,can he stoppedwhile the arbor-continues to turn, .thuseliminatingskickbaekito -a greatextent. Theseclutchdevices make blade changingrrnostmdifiicult,.however, :as -the blade can .be clamped by-nailasset-forth abovebut a wrenchonra tight saw stud will merely turn thearbor-with respect to the bladeand will not loosen the stud from thearbor.

To overcome these difliculties and for safety to the operator, applicanthas provided the arbor :lockingplate 18 splined or otherwise positivelyattached to arbor 13 for rotation therewith.

Locking plate 18 (-Fig. 6) is formed with ar plurality of lockingsockets or notches'50 on its perimeter to selectively' receive a lockpin 52 that is normally yieldingly. held out of engagement with thenotches by a compression spring 54. Lock pin 52 is .slidably mounted inthe wall of housing 10 and a suitable bearing member 56 spaced therefromin the housing. It extends outwardly beyond the wall of housing 10 toform a thumb portion 58 and at its other end 60 is adapted to be pressedinto a locking notch 50.

At its outer end, but within the housing 10, lock pin 52 may havea-roller stop pin 55 mounted therein that forms a seatfor spring 54atone end while the spring may be seated against bearing member 56 at itsother end.

From this description-it will be understood that when an operator wishesto remove a saw blade 21, he will press in on lock pin 52 and apply asuitable wrench to saw stud 23. If no locking notch is immediately inplace to receive pin 52, a slight turn of the stud and arbor will bringone into locking relationship. Regardless of the presence of a bladeclutch or not, the arbor is locked against rotation and the stud may beremoved without trouble.

I claim:

1. The combination with a portable power driven saw having a supportingfoot member, a motor housing mounted onsaid foot member in verticallyadjustable relationship therewith, a motor mounted in said housinghaving a driven saw blade arbor operatively connected thereto with saidarbor extending outwardly from said housingand having a saw blademounted thereon, of a guard member for the upper part, said saw bladerotatably mounted on said saw blade arbor for rotation with respect tosaid housing and presenting a forward and a rearward portion, theforward portion of said guard member extending adjacent said footsupport member in the lowest vertical adjustment between said footmember and said housing, a cam slot mounted in one of said members anda. cam actuating element mounted in the other of said members andextending into said slot member whereby on vertical adjustmentof saidhousing with respect to said foot support member, said guard member willbe rotated with respect to said housing to 'hold the forward portion ofsaid guard member adjacent said foot member.

2. In a portable hand held saw the combination with a saw arbor, a sawblade mounted thereorn power means for driving said blade, a guardmember for said saw blade mounted coaxially of said .saw blade, a footsupporting member, said guard member extending adjacent said footsupporting member at both ends in the full cutting position of saidblade, and means for manipulating said arbor, blade, and guardmemberassernbly for vertically cutting adjustment with respect to saidfoot supporting member, of continuous safety guard means including saidguard member being rotatably mounted on said saw, and cam meansassociated with said guard member and said foot member for rotating saidguard member to retain such forward end in continued adjacent positionwith said foot member on any vertical cutting adjustment.

3. In a power saw including a supporting foot member, a power-driven sawarbor, a circular saw blade mounted on said saw arbor, means forsupporting said saw arbor in vertically adjustable relationship withrespect to said supporting member, a guard member mounted coaxially ofand surrounding at least'the upper portion of said saw blade, said guardmember being rotatable about the axis of said saw arbor, a cam slot insaid guard member above the foot portion of said supporting foot member,a cam pin fixed on said supporting foot member and extending into saidcam slot, said cam slot being so shaped that as a saw arbor is adjustedvertically the 'said guard will be rotated about the axis of said sawarbor to be retained in a substantially constant guarding position withrespect to said saw blade.

4. In a power saw including a supporting foot member, a power-driven sawarbor, a circular saw blade mounted on said arbor, means for supportingsaid arbor in vertical- .ly adjustable relationship on said supportingfoot member,

and a guard member mounted coaxially of and surrounding at least theupper portion of said saw blade, said guard member being rotatableabout'the axis of said arbor and presenting a forward and a rearwardportion adjacent said foot member when said arbor is adjustedto itsposition closely adjacent said supporting foot member, means to retainsaid forward portion of said guard member close to'said supporting footmember in all adjusted positions of said arbor, said means comprisinginter-engagingcam slot and cam pin means fixed one to said supportingfootmember and the other to said guard member, said cam slot being soshaped that as said arbor is adjusted vertically said cam pin moving insaid cam slot causes said guard member to rotate about the axis of saidarbor to retain said forward portion adjacent said supporting footmember.

References Cited in the file of this patent UNITED STATES PATENTS1,813,231 Crowe July 7, 1931 1,848,330 Emmons Mar. 8, 1932 2,586,530Godfrey Feb. 19, 1952 2,646,090 Kluck July 21, 1953 2,765,824 Hartmannet al. Oct. 9, 1956 2,782,813 Dudek Feb. 26, 1957

